1. Field of the Invention
This invention relates to a single-pass drip-type coffee maker in which water from a reservoir is conducted through a flow-through heater and then to a spout overhanging the coffee bed over a coffee receiver. The receiver sits on a keep-warm plate heated by the flow-through heater. The invention relates to means for controlling the temperature of the water delivered through the spout.
2. Description of the Prior Art
In the prior art, there are a number of flow-through heater-type coffee makers. An example is shown in the U.S. Pat. No. 4,095,086 which issued June 13, 1978 to Ohnmacht. A problem that has been prevalent in prior art devices is that the heating means does not heat the water to a sufficient temperature during the first minutes of operation to extract satisfactorily the coffee essence from the coffee bed. Further, in prior devices, even well into the coffee-making cycle, the temperature of the extracting water as delivered to the coffee bed is not sufficiently hot. Preferably, the water temperature, as it reaches the bed in a single-pass coffee maker, should be approximately 200.degree..
Typically, the single-pass flow-through coffee maker of the art comprises a keep-warm plate on which the coffee receiver or carafe disposed. The underside of the plate has secured to it a combination heating element and water conduit. One end of the conduit is connected to the water reservoir and the other to a riser leading to the spout. A check valve is disposed in the conduit between the reservoir and the flow-through heater, blocking the movement of the water in the direction towards the reservoir. As the water heats, steam is developed creating pressure in the water heater, driving the water up the riser and out the spout. It is this general type of device to which the present invention is an improvement.